That's not everything, but it's enough to understand the issue I'm having.

Recently I have had random "pops" through whichever set of monitors are on AND the headphone output. These are single pops, not bursts of static. They're irregular and don't seem to be triggered by anything I'm doing on the computer.

In the interest of troubleshooting, and in consultation with Audient tech support, I have done the following so far:
* disconnected everything from my interface except the A and B speakers
* moved the interface's power supply to a different surge protector
* swapped out the USB cable on the interface
* swapped the USB jack into which the interface is plugged
* re-installed the interface's firmware and software.

I'm currently down to a bare-bones setup with no input devices connected to the interface. I'm basically in playback only mode, and I'm still hearing the random pops.

Here are some things that recently changed in my setup concurrent with this issue:
* I disassembled my rig and moved it all to another wall in the same room.
* My gear is plugged into different outlets, but in the same room/same circuit.
* I may have various USB plugs in different outlets than they were in before moving my desk, either on the Mac Pro itself or the PCI USB 3 expansion card
* I replaced my primary powered monitors with a different set (same cables).
* I added the B set of monitors with the stereo receiver which was not part of my rig before.
* I have recently recorded several songs, potentially eating up space on my primary drive.
* I have been connected to the internet using WiFi as I moved too far from my router to connect via ethernet.

I've read about sorts of one-off issues and fixes for similar symptoms of various makes. People have found relief from this in weird ways. For example, disabling power management or using a ground lift for the power to one's interface and/or monitors.

My question for the forum is whether you've experienced similar issues and have any other ideas or suggestions for me.